A scientist is studying the effects of cell phone use on headache rate. She identifies 30 people who use cell phones and 30 who do not. Each of the 60 people is given a questionnaire designed to determine headache frequency. None of the 60 people who participated in the study knew they were part of a study. Which statement is true?

Answers

Answer 1

Answer:

C this is a double blind study.

Step-by-step explanation:

Both groups in the experiment are blind (don't know they are in an experiment). If this answer is incorrect then its A.

Answer 2

Answer:

observational study

Step-by-step explanation:
the experimenters are not blind to their own tests.


Related Questions

Helppp meeee plzzz thanks

Answers

Answer:

500+4=504

Step-by-step explanation:

Hope it helps

Mr. Evans is paid $10.40 per hour for the first 40 hours he works in a week. He is paid 1.5 times that rate for each hour after that.

Last week, Mr. Evans worked 41.75 hours. He says he earned $434.20 last week. Do you agree? Complete the explanation that supports your answer.

Answers

Answer:

Step-by-step explanation: 16,888 this are the answer

610 divided by 20 without a decimal

Answers

Answer:

30 remainder 1 or 30.5

Step-by-step explanation:

please make me brainliest

C is the midpoint of AB. D is the midpoint of AC. E is the midpoint of DC. If DE = x2 and CB = 3x2 + 3x, describe the relationship between DE and CB and find the length of AB. PLZ HELP!!

Answers

Please find illustration attached

Answer and explanation:

I have illustrated the bisection of the lines using a diagram so it's easier to solve length of AB

Comparing line DE and CB, we know that DE is half of line DC and DC is half of CB, because CB= AC

Therefore DE is a quarter of line CB because length of DE × 4 will be equal to CB

To find length of AB, we go from known to unknown

We know from what we are given that line AB has a midpoint C, CB in line AB = 3x²+3x

CB=AC because CB is half of line AB

Therefore line AB

=3x²+3x+3x²+3x

= 6x²+6x

15*PLEASE PLEASE PLEASE ANSWER VERY FAST AND CORRECT TYSM!

Answers

-2/15=13/15

Step-by-step explanation:

2/3-4/5=13/15

2/15=13/15

Find the value of θ from the following equation.(θ≤90°)​

Answers

Answer:   10°

__________________________________________________________

We are given:

Sin(6θ)  = Cos(3θ)

Solving for θ:

Simplifying Cos(3θ):

We know that:  

Cos(θ) = Sin(90-θ)

So, we can say that:

Cos(3θ) = Sin(90 - 3θ)

Finding the value of θ:

Sin(6θ) = Cos(3θ)

Sin(6θ) = Sin(90 - 3θ)                             [Since Cos(3θ) = Sin(90 - 3θ)]

6θ = 90 - 3θ                                            [If Sin(θ) = Sin(A) ; θ = A]

9θ = 90                                                   [adding 3θ on both sides]

θ = 10°                                                     [dividing both sides by 9]

Susie’s bakery is having a sale on all cookies.The bakery is offering a sale pack 4 cookies

Answers

Is there any more to the question? I cant give an answer based off of that!!

What is the answer to this geometry answer?

Answers

Mkhxvbbjff oajendbd did end dibs enfbf jdndnenebdbd djdndnxnndndn djdndbbddb
Is 90 because (10x13) is 90

A fish makes 480 dives on 10 hours at this rate how many dives did the fish do in 4 hours

Answers

Answer: 1200

Step-by-step explanation:

Answer:

192

Step-by-step explanation:

First, you would divide 480 by 10 to get 48 because you divide by the number of hours.

Then, multiply 48 by 4 to get your answer.

The answer: 192

Sara hired her brother James to help her sell
lemonade. Sara agreed to pay James $1.00, plus
$0.10 for each glass of lemonade that he sold.
Sara paid James $3.60. How many glasses of
lemonade did James sell?

Answers

Answer:

3 Lemonade

Step-by-step explanation:

We add $1.00 with $0.10, then we get $1.10

We then divide $1.10 to the amount Sara paid

$3.60/1.10, we will get the answer 3

Graph the system of equations on your graph paper to answer the question. y = - x + 4, \qquad y = x - 2 What is the solution for the system of equations? Enter your answer by filling in the boxes.

Answers

Answer:

y=x+2

y=-x+8

Step-by-step explanation:

giving brainliest it’s due asap pls help

Answers

Answer:

AB is parallel to CD - the reasoning looks right aswell although I don't know exactly what I'm answering here.. are you asking to check it?

CAN ANYONE HELP ME ASAP?!? PLEASEEE! I’ll give brainliest!
1-4

Answers

Answer:

35 degrees

42 degrees

x = 8 degrees

x = 7 degrees

Step-by-step explanation:

1)

m <1 = 70/2 = 35 degrees

2)

m <1 = 84/2 = 42 degrees

3)

6 + 4 x = (9 x + 4) / 2

12 + 8 x = 9 x + 4

12 - 4 = x

x = 8 degrees

4)

3 x - 1 = x + 13

2 x = 14

x = 7 degrees

which value would make the statement true?
Statement- 2/?>4/12

Options- A.4
B. 6
C.12
D.24​

Answers

Answer:

C and D.

Step-by-step explanation:

2/6 = 1/3                                    4/12 = 1/3

2/4 = 1/2

2/12 = 1/6

2/24 = 1/12

if sin(x)=2/5 and tan(x)>0 what is sin(2x)

Answers

Answer:

B

Step-by-step explanation:

correct on edge

The answer is, sin (2x)=4√21/25

What is trigonometry?

Trigonometry is a branch of mathematics that studies relationships between side lengths and angles of triangles.

Here, given that,

sin(x)=2/5

and tan(x)>0

Then, cos(x)=√21/25

tan(x)=2/√21

Now, sin (2x)=2tan(x)/1+tan²(x)

                    =0.873/1.19

                    =0.733

                    =4√21/25

To learn more trigonometry click:

https://brainly.com/question/26719838

#SPJ2

Find the missing side lengths leave your answerss as radicals

Answers

Answer:

n=7

m= 7[tex]\sqrt{3}[/tex]

Step-by-step explanation:

lmk if you need work



In how many ways can a chairman and a vice-chairman of a board of 6 members can occupy their seats.​

Answers

Answer:

5

Step-by-step explanation:

Sent from my iPhone and it is the email address that you sent me

write an equation of the line with a slope of -3/4 and y-intercept of -6

Answers

Answer:

y = -3/4x - 6

Step-by-step explanation:

Answer: y = (-3/4)x - 6

How do you find the length of the side of a parallelogram?
A. slope formula
B. Midpoint formula
c.distance formula

Answers

9514 1404 393

Answer:

  C.  distance formula

Step-by-step explanation:

If you're starting from vertex coordinates, the distance formula is appropriate for finding the length of one side of a parallelogram. It will tell you the distance between two points:

  d = √((x2-x1)² +(y2-y1)²)




Three students attempt to define what it means for lines lll and mmm to be perpendicular.

Can you match the teacher's comments to the definitions?

Answers

Please find diagram attached

Answer and explanation:

Perpendicular lines are lines that meet at 90 degrees/ right angle.

The question seems to be incomplete but I will explain what perpendicular lines are in the context of lines lll and mmm, with some assumptions about the lines.

Assume that line III is 30mm long and line mmm is 25mm long, we say that line III is perpendicular to line mmm if line III meets line mmm at 90 degrees as we see in the diagram attached.

In this diagram lines AB and CD are Parallel

Answers

Answer: I need a picture to find out ;-;

Step-by-step explanation:

Answer:

if youre asking for the equation its AB=CD

Step-by-step explanation:

If youre not, you'll need to attach a file or smth :'D

Question 1 of 5 Find the difference. (12m + 1) - (5m - 4) O A. 7m + 5 O B. 17m-3 O C. 17m+ 5 D. 7 m - 3​

Answers

Answer: 7m + 5

Step-by-step explanation:

Distribute the Negative Sign:

=12m+1+−1(5m−4)

=12m+1+−1(5m)+(−1)(−4)

=12m+1+−5m+4

Combine Like Terms:

=12m+1+−5m+4

=(12m+−5m)+(1+4)

=7m+5

Use the 3 trig ratios to find each unknown side length. Round all answers to 1 decimal
Note: Diagrams are not drawn to scale.

Answers

Note: You missed to add some of the details of the question.

Hence, I am solving your concept based on an assumed graph which I have attached. It would anyways clear your concept.

Answer:

Please check the explanation.

Step-by-step explanation:

Given the right angled-triangle ABC as shown in the attached diagram

From the triangle:

Ф= ∠C = 30°

AB = 6 units

BC = y

tan Ф = opp ÷ adjacent

The opposite of ∠C = 30°  is the length '6'.

The adjacent of ∠C = 30°  is the length 'y'.

As Ф= ∠C = 30°

so

tan Ф = opp ÷ adjacent

tan 30 = 5  ÷ y

1 ÷ √3 = 5  ÷ y

y = 8.7 units

Therefore, the length of the unknown side length 'y' is 8.7 units.

q(x)=2 −2+? please solve this huhu

Answers

Answer:

I mean it would just be q(x) = 0

Step-by-step explanation:

Answer: q=0

Step-by-step explanation: Let's solve for q.

qx=2−2

Step 1: Divide both sides by x.

qx

x

=

0

x

q=0

Answer:

q=0

Graph the line y=2+1/x

Answers

2+1= 3

So is three ;-;?

Answer:

THERE U GO

Step-by-step explanation:

HOPE THIS HELPS

What is the value of x in the diagram

Answers

Answer:

17

Step-by-step explanation:

Answer:

x = 23

Step-by-step explanation:

3x + 4x + 19 = 180

7x + 19 = 180

7x = 161

x = 23

How should you improve sentence 1?
Where should you move sentence 4 to improve organization?

Answers

Answer:

by referencing the source

after sentence 2

Step-by-step explanation:

edge2020

A study found that a 95% confidence interval for the mean μ of a particular population was computed from a random sample of 1200 people and found it to be 10 ± 4. Therefore, we may conclude:_______

Answers

Answer:

95% confidence interval for the mean μ is (6,14)

The Population mean μ lies between ( 6, 14 )

Step-by-step explanation:

Explanation:-

Given random sample 'n' = 1200

95% confidence interval for the mean μ is determined by

        [tex](x^{-} -Z_{\alpha } \frac{S.D}{\sqrt{n} } , x^{-} +Z_{\alpha } \frac{S.D}{\sqrt{n} } )[/tex]

Level of significance = 95% 0r 0.05

Z₀.₀₅ = 1.96

   [tex](x^{-} -Z_{\alpha } \frac{S.D}{\sqrt{n} } , x^{-} +Z_{\alpha } \frac{S.D}{\sqrt{n} } )[/tex] = 10 ± 4

Mean of the small sample = 10

95% of confidence intervals are

                         ( 10 ±4 )

                  ( 10 -4 , 10+4)

                  ( 6 , 14 )

95% confidence interval for the mean μ lies between ( 6, 14 )

For what values of x∈[0,2π] does the graph of y=x+2cosx have a horizontal tangent?

Answers

Answer: x = pi/6 and x = pi/3.

Step-by-step explanation:

We have the function:

y = x + 2*cos(x)

It will have a horizontal tangent at the point where it's derivate is equal to zero.

Then first let's differentiate y.

y' = dy/dx = 1 - 2*sin(x).

Then we must find the value of x between 0 and 2*pi (or 0° and 360°)

y'(x) = 1 - 2*sin(x) = 0.

Let's solve that:

2*sin(x) = 1

sin(x) = 1/2.

We know that:

sin(30°) = 1/2.

and

Sin(120°) = 1/2

Then let's convert 30° into radians.

We know that:

pi = 180°.

Then:

pi/180° = 1.

30° = 30°*(pi/180°) = (30°/180°)*pi = (3/18)*pi = pi/6

120° = (120°/180°)*pi = (12/18)*pi = (1/3)*pi = pi/3.

Then the two values of x are: pi/6 and pi/3.

0,2,3,5,8,10,15,17,24,26,?​

Answers

Answer:

maybe 35 is the answer for the it

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